Conventionally, in a fuel supply device which supplies a fuel from the inside of a fuel tank to the outside of the fuel tank by a fuel pump, a tank lid unit is provided and is assembled to a through hole of the fuel tank. As a kind of tank lid unit, Patent Literature 1 discloses a tank lid unit in which a drive circuit for driving a fuel pump inside the fuel tank is accommodated.
Specifically, in the tank lid unit disclosed in Patent Literature 1, a circuit housing portion, which partitions a protection space for protecting the drive circuit from an external space of the fuel tank, is integrally molded above a lid main body portion which blocks a through hole of the fuel tank.